Peroxisome proliferator-activated receptor-gamma ligands suppress fibronectin gene expression in human lung carcinoma cells: involvement of both CRE and Sp1.
Publication/Presentation Date
9-1-2005
Abstract
Lung carcinoma often occurs in patients with chronic lung disease such as tobacco-related emphysema and asbestos-related pulmonary fibrosis. These diseases are characterized by dramatic alterations in the content and composition of the lung extracellular matrix, and we believe this "altered" matrix has the ability to promote lung carcinoma cell growth. One extracellular matrix molecule shown to be altered in these lung diseases is fibronectin (Fn). We previously reported increased growth and survival of non-small cell lung carcinoma (NSCLC) cells exposed to Fn. Thus Fn may serve as a mitogen/survival factor for NSCLC and therefore represents a novel target for anti-cancer strategies. To this end, we studied the effects of the PPARgamma ligands 15d-PGJ(2), rosiglitazone (BRL49653), and troglitazone on Fn expression in NSCLC cells and found that they were able to inhibit Fn gene transcription. Inhibition of Fn expression by BRL49653 and troglitazone, but not by 15d-PGJ(2), was prevented by the specific PPARgamma antagonist GW-9662 and by PPARgamma small interfering RNA. Working with Fn deletion and mutated promoter constructs, we found that the region between -170 and -50 bp downstream from the transcriptional start site of the promoter was involved in PPARgamma ligand inhibition. PPARgamma ligands also diminished the phosphorylation of CREB, diminished Sp1 nuclear protein expression, and prevented the binding of these transcription factors to CRE and Sp1 sites, respectively, within the Fn promoter. In summary, our results demonstrate that PPARgamma ligands inhibit Fn gene expression in NSCLC cells through PPARgamma-dependent and -independent pathways that affect both CREB and Sp1.
Volume
289
Issue
3
First Page
419
Last Page
428
ISSN
1040-0605
Published In/Presented At
Han, S., Ritzenthaler, J. D., Rivera, H. N., & Roman, J. (2005). Peroxisome proliferator-activated receptor-gamma ligands suppress fibronectin gene expression in human lung carcinoma cells: involvement of both CRE and Sp1. American journal of physiology. Lung cellular and molecular physiology, 289(3), L419–L428. https://doi.org/10.1152/ajplung.00002.2005
Disciplines
Business Administration, Management, and Operations | Health and Medical Administration | Management Sciences and Quantitative Methods
PubMedID
15908479
Department(s)
Administration and Leadership
Document Type
Article